Conventionally, a tire vulcanizing apparatus for vulcanizing an unvulcanized tire by using a vulcanizing bladder is known. In this type of tire vulcanizing apparatus, for example, a heated fluid is supplied into the vulcanizing bladder to inflate the vulcanizing bladder.
For such fluid, steam is used from a point of view of cost and heat transfer performance, for example. However, when heat is transferred to the unvulcanized tire via the vulcanizing bladder, the steam is condensed to become drain and it is possible that the drain stays in the vulcanizing bladder.
Drain like this decreases temperature of the unvulcanized tire at a part in contact with the drain of the bladder relative to the temperature of the other part of the unvulcanized tire. Therefore, vulcanization unevenness occurs, which tends to cause imbalance in physical properties and performance of the tire. Further, such temperature decrease is also a cause of deteriorating the productivity because longer time is needed to vulcanize the tire.
For example, Japanese Unexamined Patent Application Publication No. 2010-110970 (Patent Document 1) has proposed a tire vulcanizing apparatus that diffuses steam and sequentially supplies steam to an entire inside of a vulcanizing bladder thereof. In the tire vulcanizing apparatus of Patent Document 1, even if the drain stays in the vulcanizing bladder, the temperature of the drain is increased by the steam that is sequentially supplied, and the temperature difference of the unvulcanized tire is decreased.